Rib fractures are a common traumatic occurrence, where the 4th to 9th ribs are most commonly fractured. Superior rib fractures of the 1st to 3rd ribs are more commonly associated with subclavian vasculature as well as brachial plexus injury. More inferior rib fractures of the 10th to 12th ribs are associated with visceral injury, in particular, the spleen, kidney and liver¹. In general, the greater the number of fractured ribs, the more severe the causative injury.

Rib fractures can have multiple complications. These include:

1. Pneumothorax
2. Hemothorax
3. Pulmonary contusions
4. Flail chest
5. Pneumonia
6. Atelectasis

Traumatic renal injury is a relatively uncommon occurrence, which is found in 1-5% of all traumas². They are typically caused by blunt injury mechanisms, in particular, motor vehicle accidents and falls from height.

Traumatic renal injury can be graded from 1 though to 5. The grading system is defined as follows³:

• Grade I - Contusion or non-expanding subcapsular hematoma; No laceration
• Grade 2 - Non-expanding perirenal hematoma; Cortical laceration <1cm deep without extravasation
• Grade 3 - Cortical laceration > 1 cm without urinary extravasation
• Grade 4 - Laceration through corticomedullary junction into collecting system OR Vascular segmental renal artery or vein injury with contained hematoma
• Grade 5 - Shattered kidney OR renal pedicle injury or avulsion

Stable patients with grade 1 to 4 lacerations tend to be managed conservatively. Grade 5 injuries, or unstable patients with lesser grade injuries require intervention. Unstable patients may have life-threatening hemorrhage, renal pedicle avulsion or expanding retroperitoneal hematomas.

Management options are either with open surgical exploration or interventional angioembolisation. Nephrectomy is usually preferred over repair for severe lacerations, unless there is a contra-indicating factor such as a solitary kidney or bilateral kidney injury.

This patient's lower rib fractures are most likely the cause of his right kidney laceration. Note the surrounding hypodensity representing active renal artery hemorrhage. Blunt trauma is most often the cause of kidney injury, in particular deceleration injuries from motor vehicle accidents.

Case contributed by A/Prof. Pramit Phal.